> b) which are (sometimes) used to submit data in a charset other
> than ISO-8859-1.
>
> Case b) will be the increasingly common; web internationalization [2]
> makes it necessary to use the POST method for form submission.
The I18N draft does not make POST use mandatory at all. A Safe header
could equally well be used to indicate that a GET-with-body result
can be cached/reused.